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Air fuel ratio

Hemi

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Jun 17, 2018
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great_britain
Looking for guidance please, I am replacing the turbo on my 62 which has a 2h engine, what air fuel ratio would you suggest be the correct ratio ?
Cheers
 
Assuming you have a meter i'd run it at standard mix for maybe a thousand miles just to let things settle in and no harm ever came from running lean
 
Shayne thank you for this what is that figure?
 
I'm not sure there is a "correct ratio" for a diesel or how you'd measure it as the air intake isn't throttled, unlike a petrol. As Shayne has said, running lean means less power but also cooler running. EGT's are the important figures on a diesel, ideally you want an EGT guage so you can tweak the fuel to keep the temperture down during break in, especially if you're uprating the turbo for more boost.
 
To many variables but it will chug around town on your lowest fuel setting anyway , until you put your foot down and find the revs go up but nothing else happens , so turn it up a notch and go for another run .

Keep doing it until your not certain the last turn of the notch made any power difference , turn it down for a week to get used to the feel of the truck and try it again .
 
A lean petrol engine burns out valves and damages the piston crowns. The correct Air/Fuel ratio for a Petrol engine under fast idle is 14.7:1, otherwise known as 'Stoichmetrically Correct'.
From my college days and memory. Approximates value;-

The Six phases of Carburation.
1. Cold Start 7:1
2. Warm Up 10:1
3. Progression. 12:1
4. Tickover. 13:1
5. Acceleration. 10:1
6. Fast Idle. 16/18:1

Schoolboy stuff but a guide.
 
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Out of interest, what kind of fuel injection pump (FIP) is it and how are the injectors activated (FIP Pressure, cam-shaft, electronic) ?
 
The 2H is an old indirect injection engine from the 1980's so I would guess uses injectors triggered by pump pressure.
 
Then the fuel is metered by the set up of the FIP which cannot be altered and the correct injectors. The only other item that I can forsee is that the FIP advances when the boost pressure activates the advance mechanism. There are no other adjustments apart from the correct 'spill-time'.
 
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